Optical systems such as optical scanner devices for scanning a recorded image to produce a representative image use optical sensor arrays such as charged coupled device (CCD) arrays. The CCD array is situated relative to the recorded image such that the recorded image and CCD array move relative to each other, wherein the recorded image moves in relation to the optical sensor array. The sensor array converts the image into electrical signals representative of image pixels comprising the image. Typical of these optical scanner devices are multiple function machines which include the functions of a printer, facsimile machine, photocopy machine and/or optical scanner device within one machine.
In order to achieve optimal scanning quality, the optical sensor and the optical system need to be aligned, positioned and fixed in space relative to each other. For a single line CCD, five degrees of freedom (DOF) out of six DOF are essential to this alignment. The majority of scanners on the market today have active control of only four DOF; movement along the x and z axis and rotation about the y axis are controlled on the CCD device, and movement along the y axis is controlled on the lens. Consequently these scanners have very small tolerances in the rotational z direction. The typical securing method is to tighten down two screws which hold the CCD relative to the optical path. This tightening process imparts torques and forces to the CCD which move it from the optimum aligned position. Also, moving the lens in the y direction degrades the optimum alignment because (i) the optical axis is typically not parallel to the axis of movement, and (ii) mechanical imperfections in the lens and/or housing cause undesired movement in the other axes during movement in the y direction.
It would therefore be an improvement in the art to provide an optical sensor system with improved alignment capabilities, wherein the optical sensor can be aligned without causing forces moving the sensor from the optimum aligned position.